From 12c3b1ccf6a4014da077a9c1427faec588af0be1 Mon Sep 17 00:00:00 2001
From: Roman Zeyde <roman.zeyde@gmail.com>
Date: Mon, 31 Aug 2015 21:11:24 +0300
Subject: [PATCH] bignum: add specific tests for bn_mod() edge cases

---
 test_curves.py | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/test_curves.py b/test_curves.py
index 67d1808093..c511bbc97f 100755
--- a/test_curves.py
+++ b/test_curves.py
@@ -261,6 +261,13 @@ def test_mod(curve, r):
     lib.bn_mod(y, int2bn(curve.p))
     assert bn2int(y) == x % curve.p
 
+def test_mod_specific(curve):
+    p = curve.p
+    for x in [0, 1, 2, p - 2, p - 1, p, p + 1, p + 2, 2*p - 2, 2*p - 1]:
+        y = int2bn(x)
+        lib.bn_mod(y, int2bn(curve.p))
+        assert bn2int(y) == x % p
+
 POINT = BIGNUM * 2
 to_POINT = lambda p: POINT(int2bn(p.x()), int2bn(p.y()))
 from_POINT = lambda p: (bn2int(p[0]), bn2int(p[1]))